WEICHAI WD10 Service Manual - page 146
Service Manual for WD10 Diesel Engine
136
5) Positive pressure inspection method
After maintenance but before filling refrigerant,
add a small amount of gaseous refrigerant and
inflate the system with nitrogen to 1.4~1.5MPa,
maintain the pressure for 12h. If pressure drop
exceeds 0.005MPa, then it indicates that there is
system leakage. Find out the leaking position
with soap-suds.
6) Negative pressure inspection method
Pump the system into a vacuum, and check
vacuum gauge after a while, if vacuum degree
drops, then there must be leakage.
(5) A/C compressor leakage detecting process:
1) Remove the A/C compressor if find out the compressor has leakage problem during the
maintenance.
2) Prepare air source or nitrogen gas cylinder, high pressure gas of 3MPa is required.
3) Prepare vessel for leakage detection, the vessel should be big enough to hold the compressor,
pour water or ethyl alcohol into the vessel.
4) Prepare connector to connect the compressor and air source. O-shape seal ring is required for
connecting the connector and compressor.
5) Connect the connector to compressor and fix it with bolts, inflate compressor with high
pressure gas to 1.5~1.8Mpa.
6) Put the inflated compressor into vessel and observe, there is no leakage problem if bubble
doesn’t occur in 5min; if bubble occurs, marking the bubbling position with marker pen.
(6) Precautions for A/C compressor leakage detecting:
1) Note that the inflating pressure should not be too high.
2) Wear google to protect your eyes in the leakage detecting process.
3) Ensure enough observing time to avoid neglecting minor leakage.
4) After the detecting, check whether there is air in the compressor to prevent confusion.